Thermal stress during larval development reduces viral transmission blocking in Wolbachia-infected Aedes aegypti

Abstract

Currently, a worldwide threat exists from infectious arboviral diseases transmitted by Aedes mosquitoes. Different control methods have been established to limit this burden, however due to overwhelming challenges a definitive answer is still required.Recently, the heritable and endosymbiotic bacterium Wolbachia has proven promising because of its high capacity of population invasion and viral blocking capacity. This has led to candidate strains (such as wMel—native Wolbachia in fruit flies) to be used in field controls of dengue and Zika in endemic areas. However,recent discoveries suggest that this strain suffers from thermal stress, which may limit its viral blocking and population invasion capacity. Here we emulated field collected temperature data from larval breeding areas and discovered that in addition to the previously reported tendency of wMel density decline and experience maternal leakage, there is also a drop in viral blocking ability in wMel as compared to the robust blocking by wAlbB after two generations of heat-treatment. Therefore, our findings show that for efficient and effective selection of Wolbachia strains for viral obstruction in the natural setting; heat stability should be a crucial factor to be taken into consideration